CN103881365B - A kind of preparation method of ultraviolet light polymerization Alumina gel modified aqueous urethane acrylate dispersoid - Google Patents

Abstract

A kind of preparation method of ultraviolet light polymerization Alumina gel modified aqueous urethane acrylate dispersoid, acetone method is adopted to prepare photocuring aqueous polyurethane acrylate performed polymer, then triethylamine neutralization is added, add emulsifying water and obtain photocuring aqueous polyurethane acrylate emulsion, in emulsion process, introduce different content Alumina gel synthesizing organic-inorganic composite emulsion simultaneously.This inorganic composite materials has good consistency at photocuring aqueous polyurethane, and this dispersion can be widely used in the field of surface coatings such as high damage resistant, wear-resisting woodenware, metal, plastic cement.

Description

A kind of preparation method of ultraviolet curing aluminum sol modified waterborne polyurethane acrylate dispersion

technical field

The invention discloses a preparation method of an ultraviolet light-curable aluminum sol modified waterborne polyurethane acrylate dispersion, which belongs to the field of ultraviolet light-curable resins.

Background technique

At present, with the strengthening of people's awareness of environmental protection, the research on UV-curable water-based polyurethane acrylate instead of general polyurethane is becoming more and more popular and favored by many researchers. In the existing reports on the synthesis of waterborne urethane acrylate, the emulsion method or the bulk method is generally used. These methods are mostly suitable for the polymerization of isocyanates with low activity, but the post-treatment is complicated, especially the bulk method system has high viscosity, and the temperature is difficult to control. Glue and other phenomena; while the water-based UV-curable polyurethane acrylate synthesized by the acetone method has simple process, easy control of reaction, good repeatability, wide range of emulsion particle size, and high product quality.

Although UV-curable waterborne polyurethane can basically eliminate the use of reactive diluents and avoid the curing shrinkage caused by it, the process is simple, the reaction is easy to control, and the repeatability is good. It has become a new direction for the development of UV-curable coatings. However, a single light-curable water-based resin has certain disadvantages in application, such as the high brittleness of the resin with high functionality, and most of the resins are bifunctional substances, and there is a problem of poor curing performance. Antibacterial, water resistance, weather resistance and other aspects need to be further improved, so at this stage, the addition of inorganic nanomaterials often makes the dispersion widely used in the surface coating fields of high scratch resistance and wear resistance wood, metal, plastic and so on .

Contents of the invention

The purpose of the present invention is to design a dispersion system that can be widely used in the surface coating fields of high scratch-resistant and wear-resistant wood, metal, plastic and the like. Its design idea is: on the basis of photocurable polyether polyurethane prepolymer, it is designed to modify photocurable waterborne polyurethane by introducing different contents of aluminum sol. The innovation of this technology lies in the introduction of aluminum sol. The surface of aluminum sol forms hydrogen bonds with polyurethane prepolymers. Under the action of chemical bonds, silica sol exists stably in the emulsion system and acts as a filler to a certain extent. The final prepared coating film will have new functions such as scratch resistance, dirt resistance, dust resistance, and aging resistance.

The specific steps are:

(1) Preparation of aluminum sol: Add a certain amount of deionized water into a dry three-neck flask equipped with a stirrer and a thermometer, slowly add a certain amount of concentrated nitric acid while stirring, and slowly pour in Al ₂ O after the nitric acid is completely dissolved and cooled. ₃ . Heat the solution to 90°C and stir until the solution is completely dissolved to a homogeneous state to form a light blue aluminum sol.

(2) Synthesis of photocurable waterborne polyurethane acrylate prepolymer: add a certain amount of isophorone diisocyanate (IPDI) into a dry three-necked flask equipped with a stirrer and a thermometer, and add a certain amount of isophorone diisocyanate (IPDI) into the dropping funnel. Shake PPG400 and catalyst di-n-butyltin dilaurate (DBTL), add dropwise, heat up to 40°C, add dimethylol propionic acid (DMPA) after 2 hours of reaction, heat up to 60°C, react for 2 hours, and finally add acrylic acid hydroxyl Ethyl ester (HEA), the temperature was raised to 80°C, and the reaction was carried out for 4 hours; in each step, the change of the NCO value in the system was monitored by the di-n-butylamine method, and the next step was carried out when the theoretical value was reached. n(IPDI):n(PPG400):n(DMPA):n(HEA)=2:1:0.5:1, the obtained product is marked as A.

(3) Preparation of light-cured water-based polyurethane acrylate emulsion: take quantitative prepolymer A and put it into a four-necked flask, calculate the carboxyl content in the prepolymer, calculate the triethylamine content with a 1:1 molar ratio, and fill the triethylamine Put it into the dropping funnel and add it dropwise at a rate of 2-3s/drop. The reaction is carried out at room temperature. Naturally cooled to room temperature, the obtained product was denoted as B.

(4) Preparation of UV-cured aluminum sol modified water-based polyurethane acrylate dispersion: Weigh the corresponding amount of B and put it into a three-necked flask, and weigh the required proportion of aluminum sol and a certain amount of deionized water and mix evenly. Put it into the dropping funnel, add it dropwise at a speed of 2 s/drop under the condition of rapid stirring, and react for 0.5 h after the drop is completed, so that the final solid content is 15%, and the whole reaction can be carried out at room temperature.

detailed description

Example 1:

1. Preparation of aluminum sol: Add 150ml of deionized water into a dry three-necked flask equipped with a stirrer and a thermometer, slowly add 40g of concentrated nitric acid while stirring, and slowly pour in 10g of Al ₂ O ₃ after the nitric acid is completely dissolved and cooled. Heat the solution to 90°C and stir until the solution is completely dissolved to a homogeneous state to form a light blue aluminum sol.

2. Preparation of UV-curable aluminum sol modified waterborne polyurethane acrylate dispersion:

Add 9.45g of IPDI to a dry three-necked flask equipped with a stirrer and a thermometer, add 8.1g of PPG400 and 0.02g of TBDL to the dropping funnel and shake well. , the temperature was controlled at 40°C; after dropping PPG400 and reacting for another 2 hours, the -NCO content was measured by the di-n-butylamine method. When the -NCO content was lower than the theoretical value, a semi-sealed IPDI was obtained; in the four-necked bottle Add 1.60g of DMPA to the solution, because DMPA is in powder form, add it in three times, every 0.5h, and slowly raise the temperature to 60°C, so that DMPA can contact and react with the remaining -NCO as much as possible. After reacting for 2 hours, the -NCO content was measured by the di-n-butylamine method. When the -NCO content in the system was lower than the theoretical value, the second-step reaction ended. Start the third step reaction, add 2.32g HEA dropwise at a speed of 2s/drop, and slowly raise the temperature to 70°C. Highly prone to gel phenomenon, ready to drop acetone at any time; after 4 hours of reaction, take a sample to detect the infrared spectrum (-NCO content is quite small at this stage, it cannot be determined by back titration, so it can only be detected by infrared), Observe the -NCO peak, if the -NCO peak is a weak peak, add an appropriate amount of methanol to react, otherwise, continue the reaction until the requirement is met, and obtain a photocurable water-based polyurethane acrylate prepolymer, and the obtained product is marked as A ₁ .

Take 1.21g of triethylamine to neutralize A ₁ , put triethylamine into the dropping funnel, and add dropwise at a rate of 2-3 s/drop. The reaction is carried out at room temperature. The triethylamine fully reacts with the prepolymer; after the reaction is completed, the device is taken out from the oil bath, and the system is naturally cooled to room temperature to obtain a photocurable water-based polyurethane acrylate emulsion, and the obtained product is marked as B ₁ .

Take 10.0g B ₁ in a three-necked flask, mix 1.0g aluminum sol and a certain amount of deionized water evenly, put it into the dropping funnel, and start adding dropwise, so that the solid content is 15%. Finally, a UV-curable aluminum sol modified waterborne polyurethane acrylate dispersion system is obtained.

Example 2:

1. Preparation of aluminum sol: Add 150ml of deionized water into a dry three-necked flask equipped with a stirrer and a thermometer, slowly add 40g of concentrated nitric acid while stirring, and slowly pour in 10g of Al ₂ O ₃ after the nitric acid is completely dissolved and cooled. Heat the solution to 90°C and stir until the solution is completely dissolved to a homogeneous state to form a light blue aluminum sol.

2. Preparation of UV-curable aluminum sol modified waterborne polyurethane acrylate dispersion:

Add 10.3g of IPDI to a dry three-necked flask equipped with a stirrer and a thermometer, add 8.75g of PPG400 and 0.03g of TBDL to the dropping funnel and shake well, the dropping speed is 3s/drop, about 2h to finish, the reaction is carried out in a constant temperature oil bath , the temperature was controlled at 40°C; after dropping PPG400 and reacting for another 2 hours, the -NCO content was measured by the di-n-butylamine method. When the -NCO content was lower than the theoretical value, a semi-sealed IPDI was obtained; in the four-necked bottle Add 1.74g of DMPA to the solution, because DMPA is in powder form, so add it in three times, every 0.5h, and slowly raise the temperature to 60°C, so that DMPA can contact and react with the remaining -NCO as much as possible. After reacting for 2 hours, the -NCO content was measured by the di-n-butylamine method. When the -NCO content in the system was lower than the theoretical value, the second-step reaction ended. Start the third step reaction, add 2.52g HEA dropwise at a speed of 2s/drop, and slowly raise the temperature to 70°C. Highly prone to gel phenomenon, ready to drop acetone at any time; after 4 hours of reaction, take a sample to detect the infrared spectrum (-NCO content is quite small at this stage, it cannot be determined by back titration, so it can only be detected by infrared), Observe the -NCO peak, if the -NCO peak is weak, add an appropriate amount of methanol to react, otherwise, continue the reaction until the requirement is met, and obtain a photocurable water-based polyurethane acrylate prepolymer, and the obtained product is marked as A ₂ .

Take 1.32g of triethylamine to neutralize A ₂ , put triethylamine into the dropping funnel, add dropwise at a speed of 2-3s/drop, the reaction is carried out at room temperature, after the dropwise addition, react for 0.5h again, so that The triethylamine fully reacts with the prepolymer; after the reaction is completed, the device is taken out from the oil bath, and the system is naturally cooled to room temperature to obtain a photocurable water-based polyurethane acrylate emulsion, and the obtained product is marked as B ₂ .

Take 10.0g of B2 in a three _- necked flask, mix 0.5g of aluminum sol and a certain amount of deionized water evenly, put it into the dropping funnel, and start adding dropwise, so that the solid content is 15%. Finally, a UV-curable aluminum sol modified waterborne polyurethane acrylate dispersion system is obtained.

Claims (1)

1. a preparation method for ultraviolet light polymerization Alumina gel modified aqueous urethane acrylate dispersoid, is characterized in that, comprises the steps:

(1) preparation of Alumina gel: add a certain amount of deionized water in the dry there-necked flask that agitator, thermometer are housed, slowly add a certain amount of concentrated nitric acid while stirring, after nitric acid dissolves cooling completely, slowly pour Al into ₂o ₃, solution is heated to 90 DEG C, is stirred to after solution is dissolved to homogeneous state completely and forms light blue Alumina gel,

(2) synthesis of photocuring aqueous polyurethane acrylate prepolymer: add a certain amount of isophorone diisocyanate (IPDI) in the dry there-necked flask that agitator, thermometer are housed, in dropping funnel, add the positive fourth tin (DBTL) of a certain amount of PPG400 and catalyst dibutyltin cinnamic acid two shake up, drip, be warming up to 40 DEG C, reaction 2h; Add dimethylol propionic acid (DMPA) afterwards, be warming up to 60 DEG C, reaction 2h; Finally add Hydroxyethyl acrylate (HEA), be warming up to 70 DEG C, reaction 4h; Wherein every single step reaction is all with the change of nco value in Di-n-Butyl Amine method monitoring system, when reaching theoretical value, carry out next step reaction, n (IPDI): n (PPG400): n (DMPA): n (HEA)=2: 1: 0.5: 1, the product obtained is designated as A

(3) preparation of photocuring aqueous polyurethane acrylate emulsion: get quantitative prepolymer A and load four-hole boiling flask, calculate carboxyl-content in prepolymer, triethylamine content is calculated with 1: 1 mol ratio, triethylamine is loaded in dropping funnel, the speed of dripping with 2 ~ 3s/ drips, and reaction is carried out, after dripping at normal temperatures, react 0.5h again, triethylamine and prepolymer are fully reacted; After having reacted, taken out by device from oil bath pan, system is naturally cooled to room temperature, the product obtained is designated as B,

(4) preparation of ultraviolet light polymerization Alumina gel modified aqueous urethane acrylate dispersoid: take respective amount B and load in there-necked flask, and take the Alumina gel of required ratio and a certain amount of deionized water mixes, load in dropping funnel, the speed of dripping with 2s/ when rapid stirring drips, drip off rear reaction 0.5h, make last solid content be 15%, whole reaction normal temperature carries out.